During the development of wells, in particular oil wells, submersible pump units are used which are equipped with a drive, the dimensions of which should not exceed the diameter of the well. The electric motors usually used as power drives of submerged units, taking this requirement into account, have a large length-to-diameter ratio.
An electric motor is known which comprises a body, with a laminated stator core arranged therein, in the slots of the tooth zone of which multiturn sections of a two-layer winding are disposed with face parts and a rotor spaced from the stator. In that construction the sections of the two-layer winding are disposed in slots open from the side of the face, wherein the sections may be formed by turns of wire that has a round or rectangular cross section depending on the power of the machine (V. V. Dombrovsky, G. M. Khutoretsky, "Basics of Designing Alternating Current Motors," Leningrad, Energiya, 1974, p. 349, FIGS. 8-29).
However, when there is a large ratio of the length of the electric motor to the diameter (L/d.gtoreq.10), it is impossible in practice to make a winding of sections laid into slots from the side of the gap.
A submersible electric motor for a pump is also known, which includes a body, with a laminated stator core arranged therein, in the slots of the tooth zone of which multiturn sections of a two-layer winding are disposed with face parts, and a rotor spaced from the stator (prospectus of the "Konnas" firm--Submersible electric motors).
This motor has a large length-to-diameter ratio, which excludes the arrangement of a two-layer winding with preliminary formed multiturn sections in the slots of the tooth zone of a laminated core. In such a motor the sections of the winding are made of round wire by the method of broaching through slots. However, when wire with a round cross section is used the filling factor of the winding in the slot is small (the ratio of the cross section of copper to the cross section of the slot), which is accompanied by an increase of the weight and size of the motor, a relatively large thickness of the layer of impregnation compound is required, which increases the thermal resistance for losses in the copper and makes the release of heat into the environment more difficult.
The method of assembling a motor by broaching wire through a slot, including forming sections of the winding directly in the slot, results in the necessity for rewinding in the case of insufficient electrical strength or damage to the insulation, and also makes the step of laying slot insulation more difficult.